Field of the Invention
The invention generally relates to radomes and more specifically to aircraft radomes having localized areas with different radio signal attenuation properties.
Related Technology
A radome is a structural, weather proof enclosure that protects a radar or radio antenna. Radomes protect antenna surfaces from weather and/or conceal antenna electronic equipment from view. Radomes also protect personnel from being injured from moving parts of the antenna. Radomes also improve the aerodynamic profile of an aircraft in the vicinity of the radome.
Radomes may have different shapes, such as spherical, geodesic, planar, etc., based on the intended use. Radomes are often made from fiberglass, PTFE coated fabrics, plastics, or other low weight, but structurally strong materials.
Fixed wing aircraft often use radomes to protect radar or radio antennas that are disposed on the aircraft body. For example, many aircraft include radomes that take the form of a nose cone on the forward end of the aircraft body to protect forward looking radar antennas, such as weather radar antennas. Radomes may also be found on the top, bottom, or aft parts of the aircraft body when the radome is protecting a radio communications antenna (e.g., a satellite communications antenna), or on the bottom of aircraft when protecting radio antennas for ground based communication. In these cases, the radomes may look like blisters or small domes on the aircraft body.
Generally, radomes must be large enough to allow free movement of the radar or radio antenna parts. For example, most weather radar antennas are gimbaled for movement about multiple axes. As a result, the weather radar antenna can be pointed in virtually any direction to look for weather in the vicinity of the aircraft. Thus, the radome must have uniform signal transmission and reception properties in all directions so that the radar antenna may be properly calibrated. Additionally, it may be desirable to produce radomes having structural properties that allow them to maintain their shape (so as not to change aerodynamic characteristics of the airframe) even when hit by foreign objects (such as birds) during flight. Because the radome must have uniform signal transmission and reception properties combined with structural strength aircraft radomes the signal transmission and reception properties are often compromised to ensure that the strength requirements are met.